/Engine/Source/Runtime/Landscape/Classes/LandscapeComponent.h
Generate a key for this component's layer allocations to use with MaterialInstanceConstantMap.
static [FString](API\Runtime\Core\Containers\FString) GetLayerAllocationKey ( const [TArray](API\Runtime\Core\Containers\TArray)< [FWeightmapLayerAllocationInfo](API\Runtime\Landscape\FWeightmapLayerAllocationInfo) > & Allocations, [UMaterialInterface](API\Runtime\Engine\Materials\UMaterialInterface) * LandscapeMaterial, bool bMobile )